SIP ALG (Application Layer Gateway) is a feature which is enabled by default in most Technicolor routers and inspects VoIP traffic as it passes through and modifies the messages on-the-fly.
In few situations this is useful, but in most situations SIP ALG can cause problems using the service. Very often, SIP ALG is poorly implemented causing VoIP messages to be modified in a harmful way or simply corrupts them. In such cases you may experience issues registering your handset, one-way or no audio, unable to receive calls, and issues with Busy Lamp Field (BLF) and Message Waiting Indicators (MWI).
This guide explains how to disable SIP ALG on the following models:
For the Technicolor TG589VAC or Technicolor TG588v v2 please see this guide.
telnet 192.168.1.254
and hit Enter
Note Windows Vista/7 may not have Telnet installed by default. Please click on Start → Control Panel → Programs → Programs and Features → Turn Windows Features on or off → Ensure TELNET CLIENT is checked and click OK.
connection unbind application=SIP port=5060
and hit Enter
saveall
and hit Enter to apply and make this setting permanent.
exit
and hit Enter to exit.
Different Technicolor routers may have different instructions. Please see list below for instructions for your particular device.
For further information please contact the retailer from whom you purchased the Technicolor router.
If you purchased the Technicolor from SureVoIP then SIP ALG will already be disabled.
We suggest purchasing a router more suitable for business use with a better security track record, such as a DrayTek router. Contact us and we will be happy to provide a quote.